The main() method of your application does not need to be aware of all of
the options used throughout your program; they are all automatically loaded
when the modules are loaded. Your main() method can parse the command line
or parse a config file with:

If type is given (one of str, float, int, datetime, or timedelta)
or can be inferred from the default, we parse the command line
arguments based on the given type. If multiple is True, we accept
comma-separated values, and the option value is always a list.

For multi-value integers, we also accept the syntax x:y, which
turns into range(x, y) - very useful for long integer ranges.

help and metavar are used to construct the automatically generated
command line help string. The help message is formatted like:

--name=METAVAR help string

group is used to group the defined options in logical groups. By default,
command line options are grouped by the defined file.

Command line option names must be unique globally. They can be parsed
from the command line with parse_command_line() or parsed from a
config file with parse_config_file.